Heavy-handed and often ponderous, Mosley’s second volume of paired Crosstown to Oblivion novellas (after The Gift of Fire/On the Head of a Pin) doesn’t hold a candle to his subtle and nuanced crime fiction. In “Merge,” the Earth is invaded by beings that first manifest as dead branches; when one appears in the living room of Raleigh Redman in 2007, he begins a relationship with it. The creature, whom Redman unimaginatively dubs Wood, reveals that beings from its planet need to merge with non-human Earth life to survive. The leaden prose (“I was the dregs at the bottom of a coffee cup trying to imagine what it was like to be cream”) adds little to a familiar trope. “Disciple” starts more promisingly, with its narrator trapped in a dreadful data-entry job before he is positioned to become “a hero to the peoples of infinity” by saving civilization. These tales are, alas, dull rather than thought provoking. Agent: Gloria Loomis, Watkins Loomis. (Oct.)